The compound 2-(4-methylthiazol-5-yl)ethyl nitrate:
is known to interact with amino acid neurotransmitter receptors such as the NMDA receptor and the γ-aminobutyric acid type A (GABAA) receptor. This compound is also known to stimulate cerebral soluble guanylyl cyclase (GCase). As such, this compound is useful for its neuroprotective properties, and effecting cognition enhancement. See, e.g., U.S. Pat. No. 6,310,052. It has been found that new solid forms of 2-(4-methylthiazol-5-yl)ethyl nitrate can be prepared as the maleate salt form. This salt form exhibits new physical properties that can be exploited in order to achieve new properties, making it useful as a drug substance.